What is your ferritin threshold to prescribe iron to female adolescent athletes who have symptomatic iron deficiency without anemia?

Since ferritin should be truly reflective of iron levels as we should not expect elevated hepcidin levels in a young athlete. There, I would use 30 ng/mL which has a 98% specificity and 92% sensitivity for absent marrow hemosiderin. Also, since there is expected ongoing iron loss (0.6 mg/L of sweat ...